package Expe6;

/**
 * @Author sy
 * @Date 2022/9/27
 */

public class Expe6T1 {
    public static void main(String[] args) {
        Circle c1 = new Circle();
        c1.Circle(6);
        double c = 2*Math.PI*c1.radius;
        System.out.println(c);
    }
}
class Circle {
    double radius;

    public void Circle(double radius) {
        this.radius=radius;

    }
//    public double getRadius(){
//        return radius;
//    }
//    public void setRadius(){
//        this.radius=radius;
//    }
}
